Press-in element for pressing into a non-pierced or pierced component and also method for the manufacture of the press-in element

ABSTRACT

Described is a press-in element for pressing into a non-pierced or pre-pierced component. The press-in element has a head part having a ring surface confronting the component and a neck part which projects away from the ring surface, i.e. from the component contact side. The head part further has a ring-like projection surrounding the neck part with a radial spacing and projecting away from the ring surface. The neck part has a radially outwardly projecting ring bead, which can be formed as a continuous ring bead or as a ring bead interrupted at points. The apex of the ring bead has an axial spacing from the ring surface which is larger than the axial spacing of the apex of the ring-like projection from the ring surface, which lies radially within this projection and together with it and the ring bead forms a pocket which receives material of the component.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/178,086 filed Jul. 23, 2008, which claims priority of German patentapplication No. 10 2007 034 987.6 filed Jul. 26, 2007, and the completecontents of all of the applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a press-in element for pressing into anon-pierced or pre-pierced component, in particular into a sheet metalpart, and also to a method for the manufacture of such a press-inelement.

BACKGROUND OF THE INVENTION

Press-in elements are known, for example from document EP 0678679 B 1.There an element which can be inserted into a sheet metal part isclaimed which consists of a shaft part and a head part formed in onepiece thereon, with the element having concave peripherally closedfields at its underside which serves as a contact surface and also atleast one recess extending spirally around the shaft part. The spiralrecess is preferably formed by a thread groove consequently also boundedby a thread turn which can be regarded as a ring bead. The elements canbe realized as a nut element or as a bolt element. The element describedthere has proved itself in practice but is however not necessarilysuited for usually very thick sheet metal parts (for example with athickness of 4 mm or larger).

A modified variant of the elements is furthermore known from EP 0958100B1 and indeed there in the form of a bolt element which can beintroduced in self-piercing manner into a sheet metal part, but whichcan also be introduced into a pre-pierced metal sheet. The element is inparticular suitable for being used in relatively thin metal sheets, i.e.of up to approximately 2 mm thickness. The design of the element in theregion of the head part corresponds largely to the design of the elementin accordance with the above-named document EP 0678679 B1.

Furthermore, reference should be made at this point to WO 94/01688 whichdescribes a press-in part as a fastener element in the form of a bolt, ascrew or an internal thread carrier acting as a type of nut and indeedin order to obtain a joint to a sheet metal part which is resistant topress-out and rotation. In this connection the element has head part oflarger diameter having a contact surface substantially radial to thelongitudinal axis, a shaft part of smaller diameter extending at oneside in the axial direction beyond the contact surface and, in thetransition region between the head part and the shaft part, a radiallyoutwardly open restriction concentric to the longitudinal axis as a ringspace for the accommodation of the sheet metal material. The radiallyoutwardly open restriction is formed by a ring projection which extendsin the radial direction and surrounds the shaft part.

In all the above explained known elements the sheet metal material ismoved radially into a ring recess or a thread turn formed by the ringprojection or a thread turn by a die button arranged below the sheetmetal part which has a special form in order to bring about thismaterial flow, i.e. into the radially open ring recess and optionallyinto the concave fields. This manner of proceeding is entirelypracticable for sheet metal parts up to about 2.5 or 3 mm. However, whenthe sheet metal part becomes significantly thicker it is not possible orhardly any longer possible to introduce sheet metal material into thecorresponding ring recess by the action of a die button.

SUMMARY OF THE INVENTION

The object of the present invention is to provide help here by providingan element which can also be used in thick sheet metal parts, i.e. withsheet metal thicknesses of 3 mm or larger (but also in thinner sheetmetal if required), but nevertheless to ensure that material of thesheet metal parts can be pressed into a corresponding ring recess of theelement making a special design of the die button unnecessary.Furthermore, the element should be made self-piercing, at least in someembodiments and it should moreover enable a good resistance againstrotation relative to the sheet metal part when the element is formed asa nut element or as a bolt element.

In order to satisfy this object, there is provided, in accordance withthe invention, a press-in element for pressing into a non-pierced orpre-pierced component, in particular a sheet metal part, wherein thepress-in element has a head part having a ring surface confronting thecomponent and a neck part which projects away from the ring surface,i.e. from the component contact side, wherein the head part further hasa ring-like projection surrounding the neck part with a radial spacingand projecting away from the ring surface and the neck part has aradially outwardly projecting ring bead, which can be formed as acontinuous ring bead or as a ring bead interrupted at points, with theapex of the ring bead having an axial spacing from the ring surfacewhich is larger than the axial spacing of the apex of the ring-likeprojection from the ring surface, which lies radially within thisprojection and together with it and the ring bead forms a pocket whichreceives material of the component.

In the press-in element in accordance with the invention the head partof the element is thus equipped with a ring-like projection which, onpressing of the element into the sheet metal part itself ensures thatmaterial is pressed out of the sheet metal part into the pocket formedbetween this projection and the ring bead of the neck part of theelement. Since the projection comes directly into contact with thesurface of the sheet metal part, and indeed adjacent to the pocket, onlya relatively restricted material displacement is necessary in order tofill the pocket with sheet metal material and to hereby produce therequired press-out resistance. Moreover, this material deformation takesplace without making a special form of the die button necessary. It isonly necessary for the sheet metal part to be supported on a planar endface of the die button in order to produce the material displacement bypressure onto the head part of the element and thus onto the surface ofthe sheet metal part.

The ring-like projection of the head part of the element can subdividethe said component contact surface into a radially outer ring surface,which normally forms the sheet metal contact surface and into a radiallyinner ring surface, with the radially inner ring surface bounding saidpocket or co-forming it and likewise being able to serve as anadditional contact surface. This design is however not essential. Thering-like projection which surrounds the neck part with the radialspacing could also be provided radially outwardly at the head part,whereby the surface of the head part lying radially inside the ring-likeprojection forms the sheet metal contact surface and simultaneouslybounds the said pocket.

It is particularly favourable when the element has ribs providingsecurity against rotation which extend in the axial direction and whichon being pressed into the sheet metal part form corresponding grooves inthe hole wall of the hole of the sheet metal part and take care of therequired security against rotation. In this connection the press-inelement can be manufactured in such a way that, by means of a suitablecold heading die, material can be displaced from an originallycylindrical neck part in the direction of the head part and indeed at aplurality of discrete positions around the neck part so that ribsproviding security against rotation remain between these positions andthe so displaced material form ring segments of the ring bead. In thismanner a ring bead interrupted at certain positions is formed. As aresult of the selected axial length of the ribs providing securityagainst rotation, which can for example extend over half the length ofthe neck part (with this statement in no way being intended to beregarded as restrictive since the ribs providing security againstrotation could also be longer or shorter) the ring segments of the ringbead can be formed with a radial dimension which significantly exceedsthe radial dimension of the ribs providing security against rotation.The ring bead is then of less pronounced design at the positions of theribs providing security against rotation, i.e. recesses in the ring beadcan be found at these positions which are however not disturbing butrather simply give the impression that ring bead is interrupted at thecorresponding positions. These interrupted positions can indeed producean additional security against rotation.

The element can be formed as a nut element and then has a thread whichextends through the head part and the neck part. As an alternative theelement can be provided with a shaft part and can thus be designed as abolt element. For this two different possibilities exist. On the onehand the shaft part can extend away from the end face of the head partremote from the neck part or it can extend from the end of the neck partremote from the head part.

In the first two variants, the element can be straightforwardly madeself-piercing, i.e. the free end of the neck part, that is to say theend of the neck part remote from the head part can be provided with asharp piercing edge which serves for the cutting out of a piercing slugfrom the sheet metal material. These two variants of the press-inelement can however also be used in pre-pierced sheet metal parts, i.e.the hole for receiving the press-in element is pre-pierced.

In the third variant, i.e. with the design of the element as a boltelement with a shaft part which extends away from the end of the neckpart remote from the head part, it is difficult to pierce the sheetmetal part with the shaft part as the shaft part can be hereby damaged,in particular when it is a bolt element having a thread. Nevertheless itis conceivable to pre-pierce the sheet metal part and indeed with adiameter which is smaller than the outer diameter of the neck part inthe region of the piercing edge. The element could then be so used thatthe free end of the neck part, which is formed as a piercing edge, cutsa cylindrical slug out of the sheet metal part and hereby correspondingcalibrates the sheet metal part. On pressing the neck part into thesheet metal part the ribs providing security against rotation formcorresponding grooves in the hole wall. A bolt element of this kind alsohas the advantage that the pre-piercing does not have to be made 100%accurately, because when piercing out a cylindrical piercing slug thiscan have a certain asymmetry. In other words the tolerances in such avariant can entirely be generously dimensioned, which makes the methodas a whole more price-worthy.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail in the following withreference to embodiments and to the drawings which show:

FIG. 1 a partly sectioned representation of a press-in element in theform of a nut element,

FIG. 2 a partly sectioned representation of a press-in element in theform of a bolt element,

FIG. 3 a further example in accordance with the invention for a press-inelement realized as a bolt element here also in a partly sectionedrepresentation,

FIGS. 4A-4D a series of sketches to show the manufacture of a press-inelement in accordance with the invention by means of cold heading and

FIG. 5 a representation corresponding to FIG. 1 but with the press-inelement pressed into a sheet metal part.

DETAILED DESCRIPTION OF THE INVENTION

A press-in element 10 in accordance with the invention for pressing intoa non-pierced or pre-pierced component, in particular a sheet metalpart, is shown in FIG. 1, with the press-in element 10 having a headpart 12 with a ring surface 15 facing the component and a neck part 16which projects away from the ring surface 15, i.e. from the componentcontact side 14, with the head part furthermore having a ring-likeprojection 18 which surrounds the neck part with a radial spacing andprojecting away from the ring surface and with the neck part having aradially outwardly projecting bead 20 which can be formed as acontinuous ring bead or as a ring bead which is interrupted at certainpositions (as shown in FIG. 1). The apex 22 of the ring bead has anaxial spacing a from the ring surface 15 which is larger than the axialspacing b of the tip 24 of the ring-like projection from the ringsurface 15 which is disposed radially inside of this projection andforms with it and with the ring bead a pocket 26 which receives materialof the component.

In the embodiment of FIG. 1 the component side 14 is subdivided into aradially outer ring surface 17 and a radially inner ring surface 15which are arranged radially outside and inside the ring-like projection18 respectively. This is however not essential, as the projection 18could be arranged radially outwardly at the head part 12 at thecomponent side 14.

In the illustrated embodiment ribs 30 providing security againstrotation are provided at the neck part 16 they finish at their endsadjacent the head part at the ring bead 18 of the neck part 16.Furthermore the ribs 30 providing security against rotation extend overapproximately half the axial length of the neck part 16. In thisconnection the ribs providing security against rotation extend indirections parallel to the central longitudinal axis 32 of the press-inelement. They are preferably regularly arranged at the neck part 16around the central longitudinal axis 32.

The free end 34 of the neck part, i.e. the end which is remote from thehead part is formed as a piercing section, with the peripheral edge 36of the neck part 16 being formed radially outwardly at the free end 34as a sharp piercing edge. Furthermore, the free end 34 of the neck parthas a conical recess 38 with a relatively shallow enclosed cone anglewhich, for example, lies in the range between 170 and 90°.

In the embodiment of FIG. 1 the press-in element is formed as a hollowelement and is provided in this embodiment with an inner thread 39.

As an alternative to this the press-in element can, as shown in FIG. 2,be formed as a bolt element 10′ and then has a shaft part 40 which isarranged at the side 42 of the head part 12 remote from the neck part16. Otherwise the design of the head part 12 and the neck partcorresponds extensively with the embodiment of FIG. 1 with the exceptionof the missing internal thread 39 (which is being replaced by a soliddesign of the head part with base 39′), which is why the same referencenumerals have been used in FIG. 2 as in FIG. 1 in this region and theprevious description likewise applies for the embodiment of FIG. 2 andwill not therefore be repeated. This also applies for the embodiment inaccordance to FIG. 3. In FIG. 3 a press-in element 10″ is shown as abolt element having a shaft part 50 which is arranged at the end of theneck part 16 and remote from the head part, with the shaft part 50having a smaller diameter than the outer diameter of the neck part 16.

Both in the embodiment of FIG. 2 and also in the embodiment of FIG. 3the shaft part 40 or 50 respectively is provided with an external thread39″, 39″″.

In the attachment of the press-in element in accordance with FIG. 1 to asheet metal part a component assembly arises in accordance with FIG. 5with the ring-like projection projecting away from the ring surfacehaving being pressed into the surface 62 of the sheet metal part and thematerial 64 which has been displaced hereby being located in the pocket28. In this way the press-in element is anchored in a manner securedagainst press-out in the sheet metal part. The press-in element 10 hasin this embodiment been pressed in a self-piercing manner into the sheetmetal part, i.e. the piercing edge 36 has cut a cylindrical piercingslug (not shown) out of the sheet metal part which is arranged on a(likewise not shown) die button having a cylindrical hole with adiameter corresponding to the outer diameter of the neck part 16. Thepress-in element could however also be inserted into a pre-pierced orpre-drilled sheet metal part.

In the component assembly in accordance with FIG. 5 the ribs 30providing security against rotation which are provided radiallyoutwardly at the neck part 16 are arranged in corresponding grooves 66providing security against rotation in the hole wall 68 of the piercedsheet metal part 60.

The thickness of the sheet metal part 60 in the region of the attachmentof the press-in element corresponds approximately to the spacing cbetween the said ring surface 15 of the head part and the free end 34 ofthe neck part 16, i.e. to the axial length of the neck part, is howevernormally fractionally smaller so that the sheet metal part is fullydrilled through. The previous description of the component assemblyapplies extensively also for a component assembly which arises using thepress-in element in accordance with FIG. 2 or FIG. 3. In an embodimentof the component assembly in accordance with FIG. 3 it would however bedifficult to pierce the hole in the sheet metal part by means of thepress-in element because the thread 39′″ of the shaft part would ifanything prevent this. The sheet metal part would therefore in this casehave to be pre-pierced or pre-drilled, either with a diameter whichcorresponds to that of the neck part 16 or somewhat smaller, butnevertheless larger than the outer diameter of the sheet metal part. Inthis case the sharp piercing edge 36 could pierce a hollow cylindricalpiercing slug out of the component.

In a practical embodiment of a press-in element in accordance with FIG.1 having an internal thread with the size M8, the neck part could havean axial length of 7.2 mm and an outer diameter of 13.6 mm and could beself-piercingly introduced into a sheet metal part having a thickness of7 mm. In this connection the spacing “a” amounts to 1 mm and the spacing“b” to approximately 1.5 mm. The outer diameter of the head could amountto approximately 16 mm and its thickness (axial height) to 3 mm.

The method for the manufacture of a press-in element in accordance withthe present description can take place in such a way that the ring beadis formed by axial displacement of material of the neck part.

FIG. 4A shows a blank for the press-in element 10 in accordance withFIG. 1 with the head part 12 of the element being arranged in a holder70 of a cold heading machine. The reference numeral 72 indicates a toolwhich has just been pressed against the component contact side 14 of thehead part 12 in order to form the ring-like projection 18. For thispurpose the tool 72 has a corresponding recess 74 in its end faceconfronting the head part. Since the ring projection 18 has beenfinished the tool 72 is being removed from the holder 70 in accordancewith the arrow 76 in the illustration in accordance with FIG. 4A. FIG.4B then shows a representation similar to FIG. 4A but a further tool 80is now being used, and indeed with a design which is shown in plan viewin FIG. 4C. One notes that the tool 80 has a cylindrical region 82 whichis guided on the neck part 16 of the blank and that longitudinal grooves84 are provided in the cylindrical wall of the cylindrical recess 82.Circular portions 86 are located between the longitudinal grooves 84,with the circular portions 86 serving on movement of the tool 80 in thedirection of the arrow 88 towards the holder 70 to displace or scrapeaway material from the fractional larger region of the neck part 16 inorder to form the ring bead 20, i.e. in this case ring bead segments 20which are spaced apart position-wise from one another by ribs providingsecurity against rotation which are formed by the grooves 84 between themovement 88 of the tool 80. When the tool 80 has reached its maximumapproach to the holder 70 which is limited by the spacer ring 90 thenthe manufacture of the ribs 30 providing security against rotation atthe positions of the grooves 84 and the rough form of the projection 20is finished. The tool 80 is then exchanged for a further tool 100 whichis shown in end view in FIG. 4D. This tool corresponds essentially tothe tool in accordance with FIG. 4B but with the exception that aconical surface 102 is provided which leads to the ring bead receivingthe design with tip 22 which is shown in FIG. 1.

A spacer ring 90′ is also provided here which has the same action as thespacer ring 90 in accordance with FIG. 4B and FIG. 4C. Although thegrooves 84 are shown here as rectangular grooves they could for examplebe provided with a triangular cross-section, whereby ribs providingsecurity against rotation arise with a likewise rectangularcross-section, as shown in FIG. 1.

In all embodiments all materials can be named as an example for thematerial of the press-in element which achieve the strength values ofclass 8 in accordance with the ISO standard in the context of colddeformation, for example a 35 B2 alloy in accordance with DIN 1654. Theso formed fastener elements are suitable amongst other things for allcommercially available steel materials for drawing quality sheet metalparts and also for aluminium or its alloys.

The invention claimed is:
 1. A method for the manufacture of a press-inelement intended for attachment to a component in the form of a sheetmetal part having a head part (12) having a ring surface (15)confronting the component and a neck part which projects away from thering surface (15) adapted to engage the component, the head part furtherhaving a projection (18) in the shape of a ring surrounding the neckpart with a radial spacing the projection (18) projecting away from thering surface (15) and having an apex and the neck part having a radiallyoutwardly projecting ring bead (20) with an apex (22), which is formedas a continuous ring bead or as a ring bead interrupted at points, withthe apex (22) of the ring bead having an axial spacing (a) from the ringsurface (15) which is larger than the axial spacing (b) of the apex ofthe projection (18) from the ring surface, the apex (22) of the ringbead lying radially within the projection (18) and the ring bead (20)and the projection (18) forming a pocket (26) which receives material ofthe sheet metal part (60), there being ribs (30) providing securityagainst rotating provided at the neck part (16), the ribs coming to anend at the ring bead (20) of the neck part (16) at their ends adjacentthe head part (12), the other ends of the ribs being located furtherremoved from the head part, and the ribs extend away from the ring beadand also away from the head part comprising forming the ribs and thering bead (20) by the same axial displacing of material of the neck part(16).
 2. The method in accordance with claim 1, wherein prior to thedisplacing of the material of the neck part in order to form the ringbead, processing the head part in a cold heading machine in order toform the ring-like projection.
 3. A method for the attachment of apress-in element (10; 10; 10″) for pressing into a component being oneof a non-pierced sheet metal part and a pre-pierced sheet metal part(60), wherein the press-in element has a head part (12) having a ringsurface (15) confronting the component and a neck part which projectsaway from the ring surface (15), the head part further having aprojection (18) in the shape of a ring surrounding the neck part with aradial spacing, the projection (18) projecting away from the ringsurface (15) and having an apex and the neck part having a radiallyoutwardly projecting ring bead (20) with an apex (22), which is formedas a continuous ring bead or as a ring bead interrupted at points, withthe apex (22) of the ring bead having an axial spacing (a) from the ringsurface (15) which is larger than the axial spacing (b) of the apex ofthe projection (18) from the ring surface, the apex (22) of the ringbead lying radially within the projection (18) and the ring bead (20)and the projection (18) forming a pocket (26) which receives material ofthe sheet metal part (60), there being ribs (30) providing securityagainst rotation provided at the neck part (16), the ribs coming to anend at the ring bead (20) of the neck part (16) at their ends adjacentthe head part (12), the other ends of the ribs being located furtherremoved from the head part, and the ribs extend away from the ring beadand also away from the head part comprising using the neck part with apiercing section at a free end of the neck part in order to pierce anon-pierced sheet metal part or to calibrate the hole size in a piercedsheet metal part.
 4. The method according to claim 1, comprising formingthe neck part (16) having free end (34) remote from the head part (12)as a piercing section.